Animal rights activists say they have taken three lambs from the King’s Sandringham Estate in Norfolk.
Imagery released by Animal Rising shows three women, in pink Animal Rising t-shirts, walking through a field of sheep and loading the lambs into the back of a vehicle.
The group said that the lambs would have been sent for slaughter.
Animal Rising said that the women handed themselves into police in Windsor, Berkshire at 8am on Thursday, with banners saying: “I rescued the King’s sheep”; and: “This is how we love animals”.
Animal Rising said on its website that the incident “marks the first” of its “high-profile ‘open rescues’ this summer”.
Sarah Foy, 23, one of the women involved, said: “Like anyone, animals want to live out their lives safely and without being used or exploited.
“Sadly that is not the case here at Sandringham, or anywhere they are used in our food system.
“We urgently need a national conversation about our relationship with other animals and nature.”
A Norfolk Police spokesman said: “Norfolk Police are investigating reports three lambs were stolen from a farm in West Newton, Norfolk.
“Three women aged in their 20s and 30s voluntarily attended a police station in Slough and were arrested on suspicion of theft.
“They remain in custody.”
The Sandringham Estate has been approached for comment.